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Gopalakrishnan V, Roy U, Srivastava S, Kariya KM, Sharma S, Javedakar SM, Choudhary B, Raghavan SC. Delineating the mechanism of fragility at BCL6 breakpoint region associated with translocations in diffuse large B cell lymphoma. Cell Mol Life Sci 2024; 81:21. [PMID: 38196006 DOI: 10.1007/s00018-023-05042-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 01/11/2024]
Abstract
BCL6 translocation is one of the most common chromosomal translocations in cancer and results in its enhanced expression in germinal center B cells. It involves the fusion of BCL6 with any of its twenty-six Ig and non-Ig translocation partners associated with diffuse large B cell lymphoma (DLBCL). Despite being discovered long back, the mechanism of BCL6 fragility is largely unknown. Analysis of the translocation breakpoints in 5' UTR of BCL6 reveals the clustering of most of the breakpoints around a region termed Cluster II. In silico analysis of the breakpoint cluster sequence identified sequence motifs that could potentially fold into non-B DNA. Results revealed that the Cluster II sequence folded into overlapping hairpin structures and identified sequences that undergo base pairing at the stem region. Further, the formation of cruciform DNA blocked DNA replication. The sodium bisulfite modification assay revealed the single-strandedness of the region corresponding to hairpin DNA in both strands of the genome. Further, we report the formation of intramolecular parallel G4 and triplex DNA, at Cluster II. Taken together, our studies reveal that multiple non-canonical DNA structures exist at the BCL6 cluster II breakpoint region and contribute to the fragility leading to BCL6 translocation in DLBCL patients.
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Affiliation(s)
- Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, 560 100, India
- Department of Zoology, St. Joseph's College (Autonomous), Irinjalakuda, Kerala, 680121, India
| | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
| | - Shikha Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Tonk, Rajasthan, 304022, India
| | - Khyati M Kariya
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
| | - Saniya M Javedakar
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, 560 100, India.
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India.
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2
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Kumari R, Roy U, Desai S, Mondal AS, Nair RR, Nilavar N, Choudhary B, Raghavan SC. MicroRNA, miR-501 regulate the V(D)J recombination in B cells. Biochem J 2023; 480:2061-2077. [PMID: 38084601 DOI: 10.1042/bcj20230250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 11/13/2023] [Accepted: 12/12/2023] [Indexed: 12/21/2023]
Abstract
The stringent regulation of RAGs (Recombination activating genes), the site-specific endonuclease responsible for V(D)J recombination, is important to prevent genomic rearrangements and chromosomal translocations in lymphoid cells. In the present study, we identify a microRNA, miR-501, which can regulate the expression of RAG1 in lymphoid cells. Overexpression of the pre-miRNA construct led to the generation of mature miRNAs and a concomitant reduction in RAG1 expression, whereas inhibition using anti-miRs resulted in its enhanced expression. The direct interaction of the 3'UTR of miR-501 with RAG1 was confirmed by the reporter assay. Importantly, overexpression of miRNAs led to inhibition of V(D)J recombination in B cells, revealing their impact on the physiological function of RAGs. Of interest is the inverse correlation observed for miR-501 with RAG1 in various leukemia patients and lymphoid cell lines, suggesting its possible use in cancer therapy. Thus, our results reveal the regulation of RAG1 by miR-501-3p in B cells and thus V(D)J recombination and its possible implications on immunoglobulin leukemogenesis.
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Affiliation(s)
- Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sagar Desai
- Institute of Bioinformatics and Applied Biotechnology, Bangalore 560100, India
| | - Arannya S Mondal
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Rajshree R Nair
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Namrata Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore 560100, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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3
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Prabhu DJ, Ray U, Rajeev A, Joy R, George AT, George J, Raghavan SC, John F. Correction to "Design and Synthesis of Ketenimine Sulfonamide Conjugates through Multicomponent Reactions; A Combined Cytotoxic Analysis and Computational Exploration". ACS Omega 2023; 8:47315. [PMID: 38107917 PMCID: PMC10720288 DOI: 10.1021/acsomega.3c08691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Indexed: 12/19/2023]
Abstract
[This corrects the article DOI: 10.1021/acsomega.3c05816.].
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Kumari N, Das K, Sharma S, Dahal S, Desai SS, Roy U, Sharma A, Manjunath M, Gopalakrishnan V, Retheesh ST, Javadekar SM, Choudhary B, Raghavan SC. Evaluation of potential role of R-loop and G-quadruplex DNA in the fragility of c-MYC during chromosomal translocation associated with Burkitt's lymphoma. J Biol Chem 2023; 299:105431. [PMID: 37926284 PMCID: PMC10704377 DOI: 10.1016/j.jbc.2023.105431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/07/2023] Open
Abstract
t(8;14) translocation is the hallmark of Burkitt's lymphoma and results in c-MYC deregulation. During the translocation, c-MYC gene on chromosome 8 gets juxtaposed to the Ig switch regions on chromosome 14. Although the promoter of c-MYC has been investigated for its mechanism of fragility, little is known about other c-MYC breakpoint regions. We have analyzed the translocation break points at the exon 1/intron 1 of c-MYC locus from patients with Burkitt's lymphoma. Results showed that the breakpoint region, when present on a plasmid, could fold into an R-loop confirmation in a transcription-dependent manner. Sodium bisulfite modification assay revealed significant single-strandedness on chromosomal DNA of Burkitt's lymphoma cell line, Raji, and normal lymphocytes, revealing distinct R-loops covering up to 100 bp region. Besides, ChIP-DRIP analysis reveals that the R-loop antibody can bind to the breakpoint region. Further, we show the formation of stable parallel intramolecular G-quadruplex on non-template strand of the genome. Finally, incubation of purified AID in vitro or overexpression of AID within the cells led to enhanced mutation frequency at the c-MYC breakpoint region. Interestingly, anti-γH2AX can bind to DSBs generated at the c-MYC breakpoint region within the cells. The formation of R-loop and G-quadruplex was found to be mutually exclusive. Therefore, our results suggest that AID can bind to the single-stranded region of the R-loop and G4 DNA, leading to the deamination of cytosines to uracil and induction of DNA breaks in one of the DNA strands, leading to double-strand break, which could culminate in t(8;14) chromosomal translocation.
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Affiliation(s)
- Nitu Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Kohal Das
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, India; Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | - Sumedha Dahal
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Anju Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Meghana Manjunath
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | - Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India; Department of Zoology, St Joseph's College, Irinjalakuda, Kerala, India
| | - S T Retheesh
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Saniya M Javadekar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.
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5
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Kumari N, Antil H, Kumari S, Raghavan SC. Deficiency of ligase IV leads to reduced NHEJ, accumulation of DNA damage, and can sensitize cells to cancer therapeutics. Genomics 2023; 115:110731. [PMID: 37871849 DOI: 10.1016/j.ygeno.2023.110731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 09/14/2023] [Accepted: 10/19/2023] [Indexed: 10/25/2023]
Abstract
Ligase IV is a key enzyme involved during DNA double-strand breaks (DSBs) repair through nonhomologous end joining (NHEJ). However, in contrast to Ligase IV deficient mouse cells, which are embryonic lethal, Ligase IV deficient human cells, including pre-B cells, are viable. Using CRISPR-Cas9 mediated genome editing, we have generated six different LIG4 mutants in cervical cancer and normal kidney epithelial cell lines. While the LIG4 mutant cells showed a significant reduction in NHEJ, joining mediated through microhomology-mediated end joining (MMEJ) and homologous recombination (HR) were significantly high. The reduced NHEJ joining activity was restored by adding purified Ligase IV/XRCC4. Accumulation of DSBs and reduced cell viability were observed in LIG4 mutant cells. LIG4 mutant cells exhibited enhanced sensitivity towards DSB-inducing agents such as ionizing radiation (IR) and etoposide. More importantly, the LIG4 mutant of cervical cancer cells showed increased sensitivity towards FDA approved drugs such as Carboplatin, Cisplatin, Paclitaxel, Doxorubicin, and Bleomycin used for cervical cancer treatment. These drugs, in combination with IR showed enhanced cancer cell death in the background of LIG4 gene mutation. Thus, our study reveals that mutation in LIG4 results in compromised NHEJ, leading to sensitization of cervical cancer cells towards currently used cancer therapeutics.
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Affiliation(s)
- Nitu Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Himanshu Antil
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Susmita Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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6
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Joy R, Siddiqua H, Sharma S, Raveendran M, John F, Hassan P, Gawali SL, Raghavan SC, George J. Block Copolymer Encapsulation of Disarib, an Inhibitor of BCL2 for Improved Chemotherapeutic Potential. ACS Omega 2023; 8:40729-40740. [PMID: 37929147 PMCID: PMC10621013 DOI: 10.1021/acsomega.3c05802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 11/07/2023]
Abstract
A chemical inhibitor of antiapoptotic protein, BCL2, known as Disarib, suffers poor solubility in aqueous environments; thereby limiting its potential as a chemotherapeutic agent. To overcome this limitation and enhance the therapeutic efficacy of Disarib, we have employed the encapsulation of this small molecule inhibitor within P123 copolymer matrix. Micelles were synthesized using a thin-film hydration technique, and a comprehensive analysis was undertaken to evaluate the resulting micelle properties, including morphology, particle size, intermolecular interactions, encapsulation efficiency, and in vitro release characteristics. This assessment utilized various physicochemical techniques including UV spectroscopy, FTIR spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). Disarib-loaded P123 micelle formulation denoted as P123D exhibited a well-defined particle size of approximately 29.2 nm spherical core-shell morphology. Our investigations revealed a notable encapsulation efficiency of 75%, and we observed a biphasic release pattern for the encapsulated Disarib. Furthermore, our cytotoxicity assessment of P123D micelles against mouse breast adenocarcinoma, mouse lymphoma, and human leukemic cell lines showed 40-45% increase in cytotoxicity compared with the administration of Disarib alone in the breast adenocarcinoma cell line. Enhancement in the cytotoxicity of P123D was found to be higher or limited; however, it is important to observe that the encapsulation method significantly enhanced the aqueous solubility of Disarib as it has the best solubility in dimethyl sulfoxide (DMSO) in the unencapsulated state.
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Affiliation(s)
- Reshma Joy
- Bio-organic
Laboratory, Department of Chemistry, Sacred
Heart College, Kochi 682013, India
| | - Humaira Siddiqua
- Department
of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Shivangi Sharma
- Department
of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Manthra Raveendran
- Department
of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Franklin John
- Bio-organic
Laboratory, Department of Chemistry, Sacred
Heart College, Kochi 682013, India
| | | | - Santosh L Gawali
- Chemistry
Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Sathees C. Raghavan
- Department
of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Jinu George
- Bio-organic
Laboratory, Department of Chemistry, Sacred
Heart College, Kochi 682013, India
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7
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Prabhu D, Ray U, Rajeev A, Joy R, George AT, George J, Raghavan SC, John F. Design and Synthesis of Ketenimine Sulfonamide Conjugates through Multicomponent Reactions; A Combined Cytotoxic Analysis and Computational Exploration. ACS Omega 2023; 8:38619-38631. [PMID: 37867708 PMCID: PMC10586297 DOI: 10.1021/acsomega.3c05816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 09/25/2023] [Indexed: 10/24/2023]
Abstract
Multicomponent reactions involving zwitterion generated from dimethyl acetylenedicarboxylate, aryl sulfonamide, and isocyanide to generate sulfonamide-conjugated ketenimines is reported. The synthetic strategy adopted is highly atom economical and stereoselective. Ketenimine sulfonamide analogues are key intermediates for further synthetic conversions to generate a combinatorial library of compounds. Furthermore, sulfonamide compounds are known to possess a broad spectrum of biological applications. All the novel molecules synthesized exhibit the potential to target the nonhomologous DNA end-joining (NHEJ) pathway with cytotoxic ability. Computational studies compliment the in vitro biological assays of the 8 small-molecule inhibitors. DNA double-strand breaks (DSBs) are considered as the most lethal among different DNA damages. NHEJ repairs about 70% of the DSBs generated in cells within mammals. The DNA-dependent protein kinase catalytic subunit is one of the PI3 kinases associated with NHEJ. Compounds DK01-DK08 were investigated for their ability to induce cancer cell death by treating with two leukemic cell lines where NHEJ is high. Results showed that bromoaryl (DK04)- and nitroaryl (DK05)-conjugated molecules showed excellent biological activity, having IC50 values of ∼2 μM in Nalm6 cell lines.
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Affiliation(s)
- Deepak
J. Prabhu
- Post
Graduate Research Department of Chemistry, Maharajas College, Ernakulam, Ernakulam, Kerala 682011, India
| | - Ujjayinee Ray
- Department
of Microbiology, Techno India University,
Kolkata, West Bengal 700091, India
| | - Anjaly Rajeev
- Post
Graduate and Research Department of Chemistry, Sacred Heart college (M.G University), Thevara, Kerala 682013, India
| | - Reshma Joy
- Post
Graduate and Research Department of Chemistry, Sacred Heart college (M.G University), Thevara, Kerala 682013, India
| | - Abi Thoppilan George
- Post
Graduate and Research Department of Chemistry, Sacred Heart college (M.G University), Thevara, Kerala 682013, India
| | - Jinu George
- Post
Graduate and Research Department of Chemistry, Sacred Heart college (M.G University), Thevara, Kerala 682013, India
| | - Sathees C. Raghavan
- Department
of Biochemistry, Indian Institute of Science, Bengaluru 560012, India
| | - Franklin John
- Post
Graduate and Research Department of Chemistry, Sacred Heart college (M.G University), Thevara, Kerala 682013, India
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8
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Ray U, Gopinatha VK, Sharma S, Goyary L, Choudhary B, Mantelingu K, Rangappa KS, Raghavan SC. Identification and characterization of mercaptopyrimidine-based small molecules as inhibitors of nonhomologous DNA end joining. FEBS J 2023; 290:796-820. [PMID: 36048168 DOI: 10.1111/febs.16615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/21/2022] [Accepted: 08/31/2022] [Indexed: 02/04/2023]
Abstract
Mercaptopyrimidine derivatives are heterocyclic compounds with potent biological activities including antiproliferative, antibacterial, and anti-inflammatory properties. The present study describes the synthesis and characterization of several mercaptopyrimidine derivatives through condensation of 5,6-diamino-2-mercaptopyrimidin-4-ol with various heterocyclic and aromatic aldehydes. Previous studies have shown that SCR7, synthesized from 5,6-diamino-2-mercaptopyrimidin-4-ol, induced cytotoxicity by targeting cancer cells by primarily inhibiting DNA Ligase IV involved in nonhomologous end joining, one of the major DNA double-strand break repair pathways. Inhibition of DNA repair pathways is considered as an important strategy for cancer therapy. Due to limitations of SCR7 in terms of IC50 in cancer cells, here we have designed, synthesized, and characterized potent derivatives of SCR7 using 5,6-diamino-2-mercaptopyrimidin-4-ol as the starting material. Several synthesized imine compounds exhibited significant improvement in inhibition of end joining and cytotoxicity up to 27-fold lower concentrations than SCR7. Among these, two compounds, SCR116 and SCR132, showed increased cancer cell death in a Ligase IV-dependent manner. Treatment with the compounds also led to reduction in V(D)J recombination efficiency, cell cycle arrest at G2/M phase, accumulation of double-strand breaks inside cells, and improved anti-cancer potential when combined with γ-radiation and radiomimetic drugs. Thus, we describe novel inhibitors of NHEJ with higher efficacy and potential, which can be developed as cancer therapeutics.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Vindya K Gopinatha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.,Department of Studies in Chemistry, University of Mysore, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
| | - Laijau Goyary
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
| | | | - Kanchugarakoppal S Rangappa
- Department of Studies in Chemistry, University of Mysore, India.,Institution of Excellence, Vijnana Bhavana, University of Mysore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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9
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Sharma A, Kaninathan A, Dahal S, Kumari S, Choudhary B, Raghavan SC. Exposure to endosulfan can cause long term effects on general biology, including the reproductive system of mice. Front Genet 2022; 13:1047746. [PMID: 36506329 PMCID: PMC9729358 DOI: 10.3389/fgene.2022.1047746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022] Open
Abstract
Increased infertility in humans is attributed to the increased use of environmental chemicals in the last several decades. Various studies have identified pesticides as one of the causes of reproductive toxicity. In a previous study, infertility was observed in male mice due to testicular atrophy and decreased sperm count when a sublethal dose of endosulfan (3 mg/kg) with a serum concentration of 23 μg/L was used. However, the serum concentration of endosulfan was much higher (up to 500 μg/L) in people living in endosulfan-exposed areas compared to the one used in the investigation. To mimic the situation in an experimental setup, mice were exposed to 5 mg/kg body weight of endosulfan, and reproductive toxicity and long-term impact on the general biology of animals were examined. HPLC analysis revealed a serum concentration of ∼50 μg/L of endosulfan after 24 h endosulfan exposure affected the normal physiology of mice. Histopathological studies suggest a persistent, severe effect on reproductive organs where vacuole degeneration of basal germinal epithelial cells and degradation of the interstitial matrix were observed in testes. Ovaries showed a reduction in the number of mature Graafian follicles. At the same time, mild vacuolation in liver hepatocytes and changes in the architecture of the lungs were observed. Endosulfan exposure induced DNA damage and mutations in germ cells at the molecular level. Interestingly, even after 8 months of endosulfan exposure, we observed increased DNA breaks in reproductive tissues. An increased DNA Ligase III expression was also observed, consistent with reported elevated levels of MMEJ-mediated repair. Further, we observed the generation of tumors in a few of the treated mice with time. Thus, the study not only explores the changes in the general biology of the mice upon exposure to endosulfan but also describes the molecular mechanism of its long-term effects.
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Affiliation(s)
- Anju Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Sumedha Dahal
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Susmita Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India,*Correspondence: Sathees C. Raghavan,
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10
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Paranjape AM, Desai SS, Nishana M, Roy U, Nilavar NM, Mondal A, Kumari R, Radha G, Katapadi VK, Choudhary B, Raghavan SC. Nonamer dependent RAG cleavage at CpGs can explain mechanism of chromosomal translocations associated to lymphoid cancers. PLoS Genet 2022; 18:e1010421. [PMID: 36228010 PMCID: PMC9595545 DOI: 10.1371/journal.pgen.1010421] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 10/25/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Chromosomal translocations are considered as one of the major causes of lymphoid cancers. RAG complex, which is responsible for V(D)J recombination, can also cleave non-B DNA structures and cryptic RSSs in the genome leading to chromosomal translocations. The mechanism and factors regulating the illegitimate function of RAGs resulting in oncogenesis are largely unknown. Upon in silico analysis of 3760 chromosomal translocations from lymphoid cancer patients, we find that 93% of the translocation breakpoints possess adjacent cryptic nonamers (RAG binding sequences), of which 77% had CpGs in proximity. As a proof of principle, we show that RAGs can efficiently bind to cryptic nonamers present at multiple fragile regions and cleave at adjacent mismatches generated to mimic the deamination of CpGs. ChIP studies reveal that RAGs can indeed recognize these fragile sites on a chromatin context inside the cell. Finally, we show that AID, the cytidine deaminase, plays a significant role during the generation of mismatches at CpGs and reconstitute the process of RAG-dependent generation of DNA breaks both in vitro and inside the cells. Thus, we propose a novel mechanism for generation of chromosomal translocation, where RAGs bind to the cryptic nonamer sequences and direct cleavage at adjacent mismatch generated due to deamination of meCpGs or cytosines.
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Affiliation(s)
- Amita M. Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sagar S. Desai
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
- Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Mayilaadumveettil Nishana
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Namrata M. Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Amrita Mondal
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Gudapureddy Radha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, India
- * E-mail: (BC); (SCR)
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- * E-mail: (BC); (SCR)
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11
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Abstract
RAG1 and RAG2 genes generate diversity in immunoglobulin and TCR genes by initiating the process of V-D-J recombination. RAGs recognize specific sequences (heptamer-nonamer) to generate a diversity of immunoglobulins. RAG expression is limited to early B and T cell developmental stages. Aberrant expression of RAG can lead to double strand breaks and translocations as observed in leukemia and lymphoma. The expression of RAG is tightly regulated at the transcriptional and posttranscriptional levels. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in the post-transcriptional regulation of gene expression. This study aimed to identify and catalog RAG regulation by miRNA during normal development and cancer. NGS data from normal B-cell and T-cell developmental stages and blood cancer samples have been analyzed for the expression of miRNAs against RAG1 (1,173 against human RAG1 and 749 against mouse RAG1). The analyzed data has been organized to retrieve the miRNA and mRNA expression of various RAG regulators (10 transcription factors and interacting partners) in normal and diseased states. The database allows users to navigate through the human and mouse RAG regulators, visualize and plot expression. miRAGDB is freely available and can be accessed at http://52.4.112.252/shiny/miragdb/.
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Affiliation(s)
- Sagar Sanjiv Desai
- Department of Biotechnology and Bioinformatics, Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
- Graduate Student Registered Under Manipal Academy of Higher Education, Manipal, India
| | - Saurabh Whadgar
- Department of Biotechnology and Bioinformatics, Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | | | - Bibha Choudhary
- Department of Biotechnology and Bioinformatics, Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
- *Correspondence: Bibha Choudhary,
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12
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Sharath Kumar KS, Ananda H, Rangappa S, Raghavan SC, Rangappa KS. Regioselective competitive synthesis of 3,5-bis(het) aryl pyrrole-2-carboxylates/carbonitriles vs. β-enaminones from β-thioxoketones. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Ray U, Sharma S, Kapoor I, Kumari S, Gopalakrishnan V, Vartak SV, Kumari N, Varshney U, Raghavan SC. G4 DNA present at human telomeric DNA contributes toward reduced sensitivity to γ-radiation induced oxidative damage, but not bulky adduct formation. Int J Radiat Biol 2021; 97:1166-1180. [PMID: 34259614 DOI: 10.1080/09553002.2021.1955997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE DNA, the hereditary material of a human cell generally exists as Watson-Crick base paired double-stranded B-DNA. Studies suggest that DNA can also exist in non-B forms, such as four stranded G-quadruplexes (G4 DNA). Recently, our studies revealed that the regions of DNA that can fold into G-quadruplex structures are less sensitive to ionizing radiation (IR) compared to B-DNA. Importantly, we reported that the planar G-quartet of a G4 structure is shielded from radiation induced DNA breaks, while the single- and double-stranded DNA regions remained susceptible. Thus, in the present study, we investigate whether telomeric repeat DNA present at the end of telomere, known to fold into G4 DNA can protect from radiation induced damages including strand breaks, oxidation of purines and bulky adduct formation on DNA. MATERIALS AND METHODS For plasmid irradiation assay, plasmids containing human telomeric repeat DNA sequence TTAGGG (0.8 kb or 1.8 kb) were irradiated with increasing doses of IR along with appropriate control plasmids and products were resolved on 1% agarose gel. Radioprotection was evaluated based on extent of conversion of supercoiled to nicked or linear forms of the DNA following irradiation. Formation of G-quadruplex structure on supercoiled DNA was evaluated based on circular dichroism (CD) spectroscopy studies. Cleavage of radiation induced oxidative damage and extent of formation of nicks was further evaluated using base and nucleotide excision repair proteins. RESULTS Results from CD studies showed that the plasmid DNA harboring human telomeric repeats (TTAGGG) can fold into G-quadruplex DNA structures. Further, results showed that human telomeric repeat sequence when present on a plasmid can protect the plasmid DNA against IR induced DNA strand breaks, unlike control plasmids bearing random DNA sequence. CONCLUSIONS Human telomeric repeat sequence when present on plasmids can fold into G-quadruplex DNA structures, and can protect the DNA against IR induced DNA strand breaks and oxidative damage. These results in conjunction with our previous studies suggest that telomeric repeat sequence imparts less sensitivity to IR and thus telomeres of chromosomes are protected from radiation.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Indu Kapoor
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Susmita Kumari
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India.,Department of Zoology, St. Joseph's College, Irinjalakuda, India
| | - Supriya V Vartak
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Nitu Kumari
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
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14
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Kumari R, Roy U, Desai S, Nilavar NM, Van Nieuwenhuijze A, Paranjape A, Radha G, Bawa P, Srivastava M, Nambiar M, Balaji KN, Liston A, Choudhary B, Raghavan SC. MicroRNA miR-29c regulates RAG1 expression and modulates V(D)J recombination during B cell development. Cell Rep 2021; 36:109390. [PMID: 34260911 DOI: 10.1016/j.celrep.2021.109390] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 03/07/2021] [Accepted: 06/22/2021] [Indexed: 12/13/2022] Open
Abstract
Recombination activating genes (RAGs), consisting of RAG1 and RAG2, are stringently regulated lymphoid-specific genes, which initiate V(D)J recombination in developing lymphocytes. We report the regulation of RAG1 through a microRNA (miRNA), miR-29c, in a B cell stage-specific manner in mice and humans. Various lines of experimentation, including CRISPR-Cas9 genome editing, demonstrate the target specificity and direct interaction of miR-29c to RAG1. Modulation of miR-29c levels leads to change in V(D)J recombination efficiency in pre-B cells. The miR-29c expression is inversely proportional to RAG1 in a B cell developmental stage-specific manner, and miR-29c null mice exhibit a reduction in mature B cells. A negative correlation of miR-29c and RAG1 levels is also observed in leukemia patients, suggesting the potential use of miR-29c as a biomarker and a therapeutic target. Thus, our results reveal the role of miRNA in the regulation of RAG1 and its relevance in cancer.
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Affiliation(s)
- Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sagar Desai
- Institute of Bioinformatics and Applied Biotechnology, Bangalore 560100, India; Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Namrata M Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | | | - Amita Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Gudapureddy Radha
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Pushpinder Bawa
- Institute of Bioinformatics and Applied Biotechnology, Bangalore 560100, India
| | - Mrinal Srivastava
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research (TIFR), Hyderabad 500046, India
| | - Mridula Nambiar
- Department of Biology, Indian Institute of Science Education and Research, Pune, India
| | | | - Adrian Liston
- Immunology Programme, Babraham Institute, Cambridge, United Kingdom
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore 560100, India.
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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15
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Ray U, Raghavan SC. Understanding the DNA double-strand break repair and its therapeutic implications. DNA Repair (Amst) 2021; 106:103177. [PMID: 34325086 DOI: 10.1016/j.dnarep.2021.103177] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 06/25/2021] [Accepted: 07/07/2021] [Indexed: 10/20/2022]
Abstract
Repair of DNA double-strand breaks (DSBs) and its regulation are tightly integrated inside cells. Homologous recombination, nonhomologous end joining and microhomology mediated end joining are three major DSB repair pathways in mammalian cells. Targeting proteins associated with these repair pathways using small molecule inhibitors can prove effective in tumors, especially those with deregulated repair. Sensitization of cancer to current age therapy including radio and chemotherapy, using small molecule inhibitors is promising and warrant further development. Although several are under clinical trial, till date no repair inhibitor is approved for commercial use in cancer patients, with the exception of PARP inhibitors targeting single-strand break repair. Based on molecular profiling of repair proteins, better prognostic and therapeutic output can be achieved in patients. In the present review, we highlight the different mechanisms of DSB repair, chromatin dynamics to provide repair accessibility and modulation of inhibitors in association with molecular profiling and current gold standard treatment modalities for cancer.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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16
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Dahal S, Siddiqua H, Katapadi VK, Iyer D, Raghavan SC. Characterization of G4 DNA formation in mitochondrial DNA and their potential role in mitochondrial genome instability. FEBS J 2021; 289:163-182. [PMID: 34228888 DOI: 10.1111/febs.16113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/29/2021] [Accepted: 07/06/2021] [Indexed: 12/16/2022]
Abstract
Mitochondria possess their own genome which can be replicated independently of nuclear DNA. Mitochondria being the powerhouse of the cell produce reactive oxygen species, due to which the mitochondrial genome is frequently exposed to oxidative damage. Previous studies have demonstrated an association of mitochondrial deletions to aging and human disorders. Many of these deletions were present adjacent to non-B DNA structures. Thus, we investigate noncanonical structures associated with instability in mitochondrial genome. In silico studies revealed the presence of > 100 G-quadruplex motifs (of which 5 have the potential to form 3-plate G4 DNA), 23 inverted repeats, and 3 mirror repeats in the mitochondrial DNA (mtDNA). Further analysis revealed that among the deletion breakpoints from patients with mitochondrial disorders, majority are located at G4 DNA motifs. Interestingly, ~ 50% of the deletions were at base-pair positions 8271-8281, ~ 35% were due to deletion at 12362-12384, and ~ 12% due to deletion at 15516-15545. Formation of 3-plate G-quadruplex DNA structures at mitochondrial fragile regions was characterized using electromobility shift assay, circular dichroism (CD), and Taq polymerase stop assay. All 5 regions could fold into both intramolecular and intermolecular G-quadruplex structures in a KCl-dependent manner. G4 DNA formation was in parallel orientation, which was abolished in the presence of LiCl. The formation of G4 DNA affected both replication and transcription. Finally, immunolocalization of BG4 with MitoTracker confirmed the formation of G-quadruplex in mitochondrial genome. Thus, we characterize the formation of 5 different G-quadruplex structures in human mitochondrial region, which may contribute toward formation of mitochondrial deletions.
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Affiliation(s)
- Sumedha Dahal
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Humaira Siddiqua
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Vijeth K Katapadi
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Divyaanka Iyer
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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17
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Gopalakrishnan V, Sharma S, Ray U, Manjunath M, Lakshmanan D, Vartak SV, Gopinatha VK, Srivastava M, Kempegowda M, Choudhary B, Raghavan SC. SCR7, an inhibitor of NHEJ can sensitize tumor cells to ionization radiation. Mol Carcinog 2021; 60:627-643. [PMID: 34192388 DOI: 10.1002/mc.23329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 12/30/2022]
Abstract
Nonhomologous end joining (NHEJ), one of the major DNA double-strand break repair pathways, plays a significant role in cancer cell proliferation and resistance to radio and chemotherapeutic agents. Previously, we had described a small molecule inhibitor, SCR7, which inhibited NHEJ in a DNA Ligase IV dependent manner. Here, we report that SCR7 potentiates the effect of γ-radiation (IR) that induces DNA breaks as intermediates to eradicate cancer cells. Dose fractionation studies revealed that coadministration of SCR7 and IR (0.5 Gy) in mice Dalton's lymphoma (DLA) model led to a significant reduction in mice tumor cell proliferation, which was equivalent to that observed for 2 Gy dose when both solid and liquid tumor models were used. Besides, co-treatment with SCR7 and 1 Gy of IR further improved the efficacy. Notably, there was no significant change in blood parameters, kidney and liver functions upon combinatorial treatment of SCR7 and IR. Further, the co-treatment of SCR7 and IR resulted in a significant increase in unrepaired DSBs within cancer cells compared to either of the agent alone. Anatomy, histology, and other studies in tumor models confirmed the cumulative effects of both agents in activating apoptotic pathways to induce cytotoxicity by modulating DNA damage response and repair pathways. Thus, we report that SCR7 has the potential to reduce the side effects of radiotherapy by lowering its effective dose ex vivo and in mice tumor models, with implications in cancer therapy.
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Affiliation(s)
- Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India.,Department of Zoology, St. Joseph's College (Autonomous), Irinjalakuda, Kerala, India
| | - Shivangi Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India
| | - Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Meghana Manjunath
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India.,Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Divya Lakshmanan
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Supriya V Vartak
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Vindya K Gopinatha
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mrinal Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India.,Tata Institute of Fundamental Research, Hyderabad, Telangana, India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, Karnataka, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
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18
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Javadekar SM, Nilavar NM, Paranjape A, Das K, Raghavan SC. Characterization of G-quadruplex antibody reveals differential specificity for G4 DNA forms. DNA Res 2021; 27:5934508. [PMID: 33084858 PMCID: PMC7711166 DOI: 10.1093/dnares/dsaa024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022] Open
Abstract
Accumulating evidence suggests that human genome can fold into non-B DNA structures, when appropriate sequence and favourable conditions are present. Among these, G-quadruplexes (G4-DNA) are associated with gene regulation, chromosome fragility and telomere maintenance. Although several techniques are used in detecting such structures in vitro, understanding their intracellular existence has been challenging. Recently, an antibody, BG4, was described to study G4 structures within cells. Here, we characterize BG4 for its affinity towards G4-DNA, using several biochemical and biophysical tools. BG4 bound to G-rich DNA derived from multiple genes that form G-quadruplexes, unlike complementary C-rich or random sequences. BLI studies revealed robust binding affinity (Kd = 17.4 nM). Gel shift assays show BG4 binds to inter- and intramolecular G4-DNA, when it is in parallel orientation. Mere presence of G4-motif in duplex DNA is insufficient for antibody recognition. Importantly, BG4 can bind to G4-DNA within telomere sequence in a supercoiled plasmid. Finally, we show that BG4 binds to form efficient foci in four cell lines, irrespective of their lineage, demonstrating presence of G4-DNA in genome. Importantly, number of BG4 foci within the cells can be modulated, upon knockdown of G4-resolvase, WRN. Thus, we establish specificity of BG4 towards G4-DNA and discuss its potential applications.
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Affiliation(s)
- Saniya M Javadekar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Namrata M Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Amita Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Kohal Das
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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19
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Sharma S, Varsha KK, Ray U, Siddiqua H, Jose AE, Muninarasimaiah S, Raghavan SC, Choudhary B. Acute toxicity analysis of an inhibitor of BCL2, Disarib, in rats. Sci Rep 2021; 11:9982. [PMID: 33976278 PMCID: PMC8113538 DOI: 10.1038/s41598-021-89387-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/19/2021] [Indexed: 11/09/2022] Open
Abstract
Apoptosis or programmed cell death is a highly regulated process, which eliminates unwanted and damaged cells. Inhibition of apoptosis is a hallmark of cancer cells. BCL2 family proteins are known to play a vital role in the regulation of apoptosis. Overexpression of BCL2, an antiapoptotic protein, provides the advantage of prolonged survival to cancer cells. Over the years, several BCL2 inhibitors have been investigated extensively for their anticancer potential. However, most of them were abolished before clinical use due to their side effects. Previously, we had identified and characterized a novel BCL2 inhibitor, Disarib, with the potential to eliminate tumor cells in a BCL2 specific manner leading to reduction in tumor burden in multiple mouse models. Notably, a head-to-head comparison of Disarib to ABT199, the only FDA approved BCL2 inhibitor revealed that Disarib is as potent as ABT199. Recent studies using mice revealed that Disarib did not invoke significant side effects in mice. In the present study, we have investigated the acute toxicity of Disarib in Wistar rats. The bioavailability studies following exposure of Disarib in Wistar rats revealed its maximum availability in serum at 24 h following oral administration. Acute toxicity analysis revealed that even a dose as high as 2000 mg/kg of Disarib did not cause significant toxicity in rats. There was no significant variation in blood parameters or kidney and liver functions following administration of Disarib. Histological analysis of different tissues from Disarib treated groups revealed standard architecture with no observable cellular damage. Importantly, exposure to Diasrib did not result in genotoxicity as determined by micronucleus assay. Further, solubility assays revealed that besides DMSO, Disarib is also soluble in alcohol. While the high acidic condition can increase the solubility of Disarib, even a lower percentage of alcohol with acidic conditions can improve its solubility. Thus, the toxicological profile in the current study revealed no significant side effects when Disarib was administered orally to rats.
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Affiliation(s)
- Shivangi Sharma
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, 560100, India
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
- Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India
| | | | - Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Humaira Siddiqua
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | | | | | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, 560100, India.
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20
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Ghosh D, Raghavan SC. 20 years of DNA Polymerase μ, the polymerase that still surprises. FEBS J 2021; 288:7230-7242. [DOI: 10.1111/febs.15852] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 03/02/2021] [Accepted: 03/01/2021] [Indexed: 12/22/2022]
Affiliation(s)
- Dipayan Ghosh
- Department of Biochemistry Indian Institute of Science Bangalore India
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21
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Roy U, Raghavan SC. Deleterious point mutations in T-cell acute lymphoblastic leukemia: Mechanistic insights into leukemogenesis. Int J Cancer 2021; 149:1210-1220. [PMID: 33634864 DOI: 10.1002/ijc.33527] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 12/11/2022]
Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is characterized by the leukemogenic transformation of immature T cells, which accumulate an array of genetic and epigenetic lesions, leading to a sustained proliferation of abnormal T cells. Genetic alterations in the DNA repair genes, protooncogenes, transcription factors, and epigenetic modifiers have been studied in the past decade using next-generation sequencing and high-resolution copy number arrays. While other genomic lesions like chromosomal rearrangements, inversions, insertions, and gene fusions have been well studied at functional level, the mechanism of generation of driver mutations in T-ALL is the subject of current investigation. Novel oncogenic mutations in the TP53, BRCA2, PTEN, IL7R, RAS, NOTCH1, ETV6, BCL11B, WT1, DNMT3A, PRC2, PHF6, USP7, KDM6A and an array of other genes disrupt the genetic and epigenetic homeostasis in T-ALL. In this review, we have summarized the mechanistic role of deleterious driver mutations in T-ALL initiation and progression. We speculate that the formation of non-B DNA structures could be one of the primary reasons for the occurrence of different genomic lesions seen in T-ALL, which warrants further investigation. Understanding the mechanism behind the genesis of oncogenic mutations will pave the way to develop targeted therapies that can improve the overall survival and treatment outcome.
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Affiliation(s)
- Urbi Roy
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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22
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Ghosh D, Raghavan SC. Nonhomologous end joining: new accessory factors fine tune the machinery. Trends Genet 2021; 37:582-599. [PMID: 33785198 DOI: 10.1016/j.tig.2021.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 01/08/2023]
Abstract
Nonhomologous DNA end joining (NHEJ) is one of the major DNA double-strand break (DSB) repair pathways in eukaryotes. The well-known critical proteins involved in NHEJ include Ku70/80, DNA-PKcs, Artemis, DNA pol λ/μ, DNA ligase IV-XRCC4, and XLF. Recent studies have added a number of new proteins to the NHEJ repertoire namely paralog of XRCC4 and XLF (PAXX), modulator of retroviral infection (MRI)/ cell cycle regulator of NHEJ (CYREN), transactivation response DNA-binding protein (TARDBP) of 43 kDa (TDP-43), intermediate filament family orphan (IFFO1), ERCC excision repair 6 like 2 (ERCC6L2), and RNase H2. PAXX acts as a stabilizing factor for the main NHEJ components. MRI/CYREN seems to play a dual role stimulating NHEJ in the G1 phase of the cell cycle, while inhibiting the pathway in the S and G2 phases. TDP-43 can recruit the ligase IV-XRCC4 complex to the DSB sites and stimulate ligation in neuronal cells. RNase H2 excises out the ribonucleotides inserted during repair by DNA polymerase μ/TdT. This review provides a brief glimpse into how these new partners were discovered and their contribution to the mechanism and regulation of NHEJ.
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Affiliation(s)
- Dipayan Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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23
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Nilavar NM, Raghavan SC. HIV integrase inhibitors that inhibit strand transfer interact with RAG1 and hamper its activities. Int Immunopharmacol 2021; 95:107515. [PMID: 33735713 DOI: 10.1016/j.intimp.2021.107515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/08/2021] [Accepted: 02/15/2021] [Indexed: 12/16/2022]
Abstract
Multiple steps of the retroviral infection process have been targeted over the years to develop therapeutic approaches, starting from the entry of the virus into the cell till the viral DNA integration to host genome. Inhibitors against the Human Immunodeficiency Virus (HIV) integrase is the newest among the therapies employed against HIV. Recombination activating gene 1 (RAG1) is an integral protein involved in the generation of diversity of antibodies and T-cell receptors and is one of the partners of the RAG complex. Studies have shown structural and functional similarities between the HIV integrase and RAG1. Recently, we and others have shown that some of the integrase inhibitors can interfere with RAG binding and cleavage, hindering its physiological functions. This mini review focuses on the HIV integrase, integrase inhibitors and their effect on RAG activities.
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Affiliation(s)
- Namrata M Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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24
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Maddi ER, Raghavan SC, Natesh R. Hypomorphic mutations in human DNA ligase IV lead to compromised DNA binding efficiency, hydrophobicity and thermal stability. Protein Eng Des Sel 2021; 34:6135054. [PMID: 33586762 DOI: 10.1093/protein/gzab001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 12/12/2020] [Accepted: 12/30/2020] [Indexed: 11/13/2022] Open
Abstract
Studies have shown that Lig4 syndrome mutations in DNA ligase IV (LigIV) are compromised in its function with residual level of double strand break ligation activity in vivo. It was speculated that Lig4 syndrome mutations adversely affect protein folding and stability. Though there are crystal structures of LigIV, there are no reports of crystal structures of Lig4 syndrome mutants and their biophysical characterization to date. Here, we have examined the conformational states, thermal stability, hydrophobicity and DNA binding efficiency of human DNA LigIV wild type and its hypomorphic mutants by far-UV circular dichroism, tyrosine and tryptophan fluorescence, and 1-anilino-8-naphthalene-sulfonate binding, dynamic light scattering, size exclusion chromatography, multi-angle light scattering and electrophoretic mobility shift assay. We show here that LigIV hypomorphic mutants have reduced DNA-binding efficiency, a shift in secondary structure content from the helical to random coil, marginal reduction in their thermal stability and increased hydrophobicity as compared to the wild-type LigIV.
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Affiliation(s)
- Eswar Reddy Maddi
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Ramanathan Natesh
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram, Kerala 695551, India
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Kumari N, Raghavan SC. G-quadruplex DNA structures and their relevance in radioprotection. Biochim Biophys Acta Gen Subj 2021; 1865:129857. [PMID: 33508382 DOI: 10.1016/j.bbagen.2021.129857] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND DNA, the genetic material of most of the organisms, is the crucial element of life. Integrity of DNA needs to be maintained for transmission of genetic material from one generation to another. All organisms are constantly challenged by the environmental conditions which can lead to the induction of DNA damage. Ionizing radiation (IR) has been known to induce DNA damage and IR sensitivity varies among different organisms. The causes for differential radiosensitivity among various organisms have not been studied in great detail. SCOPE OF REVIEW We discuss DNA secondary structure formation, GC content of the genome, role of G-quadruplex formation, and its relationship with radiosensitivity of the genome. MAJOR CONCLUSION In Deinococcus radiodurans, the bacterium that exhibits maximum radio resistance, multiple G-quadruplex forming motifs are reported. In human cells, G-quadruplex formation led to differential radiosensitivity. In this article, we have discussed, the role of secondary DNA structure formation like G-quadruplex in shielding the genome from radiation and its implications in understanding evolution of radio protective effect of an organism. We also discuss role of GC content and its correlation with radio resistance. GENERAL SIGNIFICANCE This review provides an insight into the role of G-quadruplexes in providing differential radiosensitivity at different site of the genome and in different organisms. It further discusses the possibility of higher GC content contributing towards reduced radiosensitivity in different organisms, evolution of radiosensitivity, and regulation of multiple cellular processes.
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Affiliation(s)
- Nitu Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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Manjunath M, Choudhary B, Raghavan SC. SCR7, a potent cancer therapeutic agent and a biochemical inhibitor of nonhomologous DNA end-joining. Cancer Rep (Hoboken) 2021; 4:e1341. [PMID: 33496064 PMCID: PMC8222562 DOI: 10.1002/cnr2.1341] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 12/11/2022] Open
Abstract
Background DNA double‐strand breaks (DSBs) are harmful to the cell as it could lead to genomic instability and cell death when left unrepaired. Homologous recombination and nonhomologous end‐joining (NHEJ) are two major DSB repair pathways, responsible for ensuring genome integrity in mammals. There have been multiple efforts using small molecule inhibitors to target these DNA repair pathways in cancers. SCR7 is a very well‐studied anticancer molecule that blocks NHEJ by targeting one of the critical enzymes, Ligase IV. Recent findings In this review, we have highlighted the anticancer effects of SCR7 as a single agent and in combination with other chemotherapeutic agents and radiation. SCR7 blocked NHEJ effectively both in vitro and ex vivo. SCR7 has been used for biochemical studies like chromosomal territory resetting and in understanding the role of repair proteins in cell cycle phases. Various forms of SCR7 and its derivatives are discussed. SCR7 is also used as a potent biochemical inhibitor of NHEJ, which has found its application in improving genome editing using a CRISPR‐Cas system. Conclusion SCR7 is a potent NHEJ inhibitor with unique properties and wide applications as an anticancer agent. Most importantly, SCR7 has become a handy aid for improving genome editing across different model systems.
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Affiliation(s)
- Meghana Manjunath
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India.,Manipal Academy of Higher Education, Manipal, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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27
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Ray U, John F, Pooppadi S, George J, Sharma S, Raghavan SC. Novel synthetic aromatic thiourea derivatives and investigations on their cytotoxic potential efficacy. J Heterocycl Chem 2021. [DOI: 10.1002/jhet.4145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ujjayinee Ray
- Department of biochemistry Indian Institute of Science Bengaluru India
| | - Franklin John
- Department of Chemistry Sacred Heart College, Thevara Kochi India
| | - Sayeesh Pooppadi
- Department of Chemistry Sacred Heart College, Thevara Kochi India
| | - Jinu George
- Department of Chemistry Sacred Heart College, Thevara Kochi India
| | - Shivangi Sharma
- Department of biochemistry Indian Institute of Science Bengaluru India
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Vindya K. Gopinatha, Ray U, Mantelingu K, Raghavan SC, Rangappa KS. Synthesis and Biological Evaluation of Theophylline Methyl 1,3,4-Oxadiazole as Anticancer Agents. Russ J Bioorg Chem 2020. [DOI: 10.1134/s106816202005009x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ray U, Vartak SV, Raghavan SC. NHEJ inhibitor SCR7 and its different forms: Promising CRISPR tools for genome engineering. Gene 2020; 763:144997. [PMID: 32783992 DOI: 10.1016/j.gene.2020.144997] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 07/21/2020] [Indexed: 12/14/2022]
Abstract
The CRISPR-Cas system currently stands as one of the best multifaceted tools for site-specific genome engineering in mammals. An important aspect of research in this field focusses on improving the specificity and efficacy of precise genome editing in multiple model systems. The cornerstone of this mini-review is one of the extensively investigated small molecule inhibitor, SCR7, which abrogates NHEJ, a Ligase IV-dependent DSB repair pathway, thus guiding integration of the foreign DNA fragment via the more precise homology directed repair during genome editing. One of our recent studies sheds light on properties of different forms of SCR7. Here, we give a succinct account on the use of SCR7 and its different forms in CRISPR-Cas system, highlighting their chemical properties and biological relevance as potent efficiency-enhancing CRISPR tools.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Supriya V Vartak
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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30
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Nilavar NM, Paranjape AM, Raghavan SC. Biochemical activity of RAGs is impeded by Dolutegravir, an HIV integrase inhibitor. Cell Death Discov 2020; 6:50. [PMID: 32566255 PMCID: PMC7293277 DOI: 10.1038/s41420-020-0281-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/26/2020] [Accepted: 04/22/2020] [Indexed: 02/03/2023] Open
Abstract
HIV is a retrovirus that infects CD4+ T lymphocytes in human beings and causes immunodeficiency. In the recent years, various therapies have been developed against HIV, including targeting the HIV specific protein, integrase, responsible for integration of HIV cDNA into host DNA. Although, integrase is specific to HIV, it has functional and structural similarity with RAG1, one of the partner proteins associated with V(D)J recombination, a process by which immune diversity is generated in humans. Currently, there are three HIV integrase inhibitors: Elvitegravir, Dolutegravir, and Raltegravir, in the market which have been approved by the FDA (USA). All three drugs are used in anti-retroviral therapy (ART). Previously, we showed that amongst the HIV inhibitors, Elvitegravir could significantly decrease B cell maturation in vivo and inhibit the physiological activities of RAGs in vitro, unlike Raltegravir. In the present study, we address the effect of second-generation integrase inhibitor, Dolutegravir on RAG activities. Binding and nicking studies showed that, Dolutegravir could decrease the binding efficiency of RAG1 domains and cleavage on DNA substrates, but not as considerably as Elvitegravir. Thus, we show that although the integrase inhibitors such as Elvitegravir show an affinity towards RAG1, the newer molecules may have lesser side-effects.
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Affiliation(s)
- Namrata M. Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012 India
| | - Amita M. Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012 India
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012 India
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31
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Ray U, Raul SK, Gopinatha VK, Ghosh D, Rangappa KS, Mantelingu K, Raghavan SC. Identification and characterization of novel SCR7-based small-molecule inhibitor of DNA end-joining, SCR130 and its relevance in cancer therapeutics. Mol Carcinog 2020; 59:618-628. [PMID: 32189406 DOI: 10.1002/mc.23186] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 12/20/2022]
Abstract
Targeting DNA repair with small-molecule inhibitors is an attractive strategy for cancer therapy. Majority of DNA double-strand breaks in mammalian cells are repaired through nonhomologous end-joining (NHEJ). It has been shown that small-molecule inhibitors of NHEJ can block efficient repair inside cancer cells, leading to cell death. Previously, we have reported that SCR7, an inhibitor of NHEJ can induce tumor regression in mice. Later studies have shown that different forms of SCR7 can inhibit DNA end-joining in Ligase IV-dependent manner. Recently, we have derivatized SCR7 by introducing spiro ring into core structure. Here, we report the identification of a novel inhibitor of NHEJ, named SCR130 with 20-fold higher efficacy in inducing cytotoxicity in cancer cell lines. SCR130 inhibited DNA end-joining catalyzed by rat tissue extract. Specificity analysis revealed that while SCR130 was specific to Ligase IV, it showed minimal or no effect on Ligase III and Ligase I mediated joining. Importantly, SCR130 exhibited the least cytotoxicity in Ligase IV-null cell line as compared with wild type, confirming Ligase IV-specificity. Furthermore, we demonstrate that SCR130 can potentiate the effect of radiation in cancer cells when used in combination with γ-radiation. Various cellular assays in conjunction with Western blot analysis revealed that treatment with SCR130 led to loss of mitochondrial membrane potential leading to cell death by activating both intrinsic and extrinsic pathways of apoptosis. Thus, we describe a novel inhibitor of NHEJ with higher efficacy and may have the potential to be developed as cancer therapeutic.
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Affiliation(s)
- Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sanjay Kumar Raul
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Vindya K Gopinatha
- Department of Studies in Chemistry, ManasaganFindo-frgotri, University of Mysore, Mysuru, India
| | - Dipayan Ghosh
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Kempegowda Mantelingu
- Department of Studies in Chemistry, ManasaganFindo-frgotri, University of Mysore, Mysuru, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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32
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Gopinatha VK, Swarup HA, Raghavan SC, Mantelingu K, Rangappa KS. Discovery of Novel Approach for Regioselective Synthesis of Thioxotriaza-Spiro Derivatives via Oxalic Acid. Synlett 2019. [DOI: 10.1055/s-0039-1690204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A vital approach for the synthesis of a range of novel thioxotriaza-spiro derivatives is described. These new heterocyclic systems are obtained via oxalic acid catalyzed reaction of α,β-unsaturated ketones in the presence of 5,6-diamino-2-mercaptopyrimidine-4-ols; thus, spiro rings are constructed in one step. Notably, this transformation involves condensation of an amino group followed by enamine reaction with alkenes and subsequent reaction promoted by oxalic acid to afford spiro compounds with excellent regioselectivity.
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Affiliation(s)
| | - Hassan A. Swarup
- Department of Studies in Chemistry, Manasagangotri, University of Mysore
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33
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Devassy G, Ramachandran R, Jeena K, Junnuthula VR, Gopinatha VK, Manju C, Manohar M, Nair SV, Raghavan SC, Koyakutty M. Simultaneous release of two drugs from polymer nano-implant inhibits recurrence in glioblastoma spheroids. prnano 2019. [DOI: 10.33218/prnano2(1).181122.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Local implant-based delivery of rationally selected combination of chemotherapeutics has some major advantages for the treatment of glioblastoma such as: (a) 100 % bio-availability locally in brain can be achieved at the tumor site (b) avoid systemic leakage and associated toxicity, and (c) simultaneous inhibition of multiple, mutually exclusive cancer mechanisms is possible. Here, we report a polymeric brain implant capable of delivering two different drugs in recur-rent glioma cells. We have selected a combination of clinically used DNA alkylating agent, Te-mozolomide, and a DNA mismatch repair protein (Ligase IV) inhibitor, SCR-7, and delivered simultaneously into tumor spheroids formed by rat glioma cells, C6. The dual-drug loaded polymeric wafer, prepared by lyophilization method, could deliver both the drugs in a controlled fashion. To test the efficacy of this system, we have optimized an in vitro recurrent model of glioma spheroids wherein, the implant released both the drugs in a sustained fashion, thereby continuously exposing the cells to DNA methylation while inhibiting the DNA repair pathways. This leads to synergistic toxicity and inhibition of tumor recurrence for extended duration compared to free drug combination.
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34
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Gopalakrishnan V, Dahal S, Radha G, Sharma S, Raghavan SC, Choudhary B. Characterization of DNA double-strand break repair pathways in diffuse large B cell lymphoma. Mol Carcinog 2018; 58:219-233. [DOI: 10.1002/mc.22921] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/18/2018] [Accepted: 10/07/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Vidya Gopalakrishnan
- Institute of Bioinformatics and Applied Biotechnology; Electronics City; Bangalore India
- Manipal Academy of Higher Education; Manipal Karnataka India
| | - Sumedha Dahal
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Gudapureddy Radha
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Shivangi Sharma
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | | | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology; Electronics City; Bangalore India
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35
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Vartak SV, Swarup HA, Gopalakrishnan V, Gopinatha VK, Ropars V, Nambiar M, John F, Kothanahally SKS, Kumari R, Kumari N, Ray U, Radha G, Dinesh D, Pandey M, Ananda H, Karki SS, Srivastava M, Charbonnier JB, Choudhary B, Mantelingu K, Raghavan SC. Autocyclized and oxidized forms of SCR7 induce cancer cell death by inhibiting nonhomologous DNA end joining in a Ligase IV dependent manner. FEBS J 2018; 285:3959-3976. [PMID: 30230716 DOI: 10.1111/febs.14661] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/23/2018] [Accepted: 09/17/2018] [Indexed: 12/17/2022]
Abstract
Nonhomologous DNA end joining (NHEJ) is the major DNA double-strand break (DSB) repair pathway in mammals. Previously, we have described a small molecule inhibitor, SCR7, which can inhibit NHEJ in a Ligase IV-dependent manner. Administration of SCR7 within the cells resulted in the accumulation of DNA breaks, cell death, and inhibition of tumor growth in mice. In the present study, we report that parental SCR7, which is unstable, can be autocyclized into a stable form. Both parental SCR7 and cyclized SCR7 possess the same molecular weight (334.09) and molecular formula (C18 H14 N4 OS), whereas its oxidized form, SCR7-pyrazine, possesses a different molecular formula (C18 H12 N4 OS), molecular weight (332.07), and structure. While cyclized form of SCR7 showed robust inhibition of NHEJ in vitro, both forms exhibited efficient cytotoxicity. Cyclized and oxidized forms of SCR7 inhibited DNA end joining catalyzed by Ligase IV, whereas their impact was minimal on Ligase III, Ligase I, and T4 DNA Ligase-mediated joining. Importantly, both forms inhibited V(D)J recombination, although the effect was more pronounced for SCR7-cyclized. Both forms blocked NHEJ in a Ligase IV-dependent manner leading to the accumulation of DSBs within the cells. Although cytotoxicity due to SCR7-cyclized was Ligase IV specific, the pyrazine form exhibited nonspecific cytotoxicity at higher concentrations in Ligase IV-null cells. Finally, we demonstrate that both forms can potentiate the effect of radiation. Thus, we report that cyclized and oxidized forms of SCR7 can inhibit NHEJ in a Ligase IV-dependent manner, although SCR7-pyrazine is less specific to Ligase IV inside the cell.
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Affiliation(s)
- Supriya V Vartak
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Vidya Gopalakrishnan
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India.,Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Vindya K Gopinatha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Virginie Ropars
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Univ Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Mridula Nambiar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Franklin John
- Department of Chemistry, Sacred Heart College, Kochi, India
| | | | - Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Nitu Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Ujjayinee Ray
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Gudapureddy Radha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Depina Dinesh
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Monica Pandey
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Hanumappa Ananda
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.,Department of Chemistry, University of Mysore, India
| | - Subhas S Karki
- KLE Academy of Higher Education and Research, KLE College of Pharmacy, Rajajinagar, Bengaluru, India
| | - Mrinal Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Jean Baptiste Charbonnier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Univ Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Bangalore, India
| | | | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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Tripathi V, Agarwal H, Priya S, Batra H, Modi P, Pandey M, Saha D, Raghavan SC, Sengupta S. MRN complex-dependent recruitment of ubiquitylated BLM helicase to DSBs negatively regulates DNA repair pathways. Nat Commun 2018. [PMID: 29523790 PMCID: PMC5844875 DOI: 10.1038/s41467-018-03393-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mutations in BLM in Bloom Syndrome patients predispose them to multiple types of cancers. Here we report that BLM is recruited in a biphasic manner to annotated DSBs. BLM recruitment is dependent on the presence of NBS1, MRE11 and ATM. While ATM activity is essential for BLM recruitment in early phase, it is dispensable in late phase when MRE11 exonuclease activity and RNF8-mediated ubiquitylation of BLM are the key determinants. Interaction between polyubiquitylated BLM and NBS1 is essential for the helicase to be retained at the DSBs. The helicase activity of BLM is required for the recruitment of HR and c-NHEJ factors onto the chromatin in S- and G1-phase, respectively. During the repair phase, BLM inhibits HR in S-phase and c-NHEJ in G1-phase. Consequently, inhibition of helicase activity of BLM enhances the rate of DNA alterations. Thus BLM utilizes its pro- and anti-repair functions to maintain genome stability. Bloom helicase is recruited to double strand breaks in an ATM dependent manner. Here the authors show that Bloom helicase is recruited to double strand breaks in an ATM and MRN dependent manner with HR and NHEJ regulated by the helicase depending on the phase of the cell cycle.
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Affiliation(s)
- Vivek Tripathi
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Himanshi Agarwal
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Swati Priya
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Harish Batra
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Priyanka Modi
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Monica Pandey
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Dhurjhoti Saha
- Institute of Genomics and Integrative Biology, CSIR, Mathura Road, New Delhi, 110025, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Sagar Sengupta
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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37
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Somu C, Hegde M, Sharath Kumar KS, Hanumappa A, Srivastava M, Harsha KB, Mohan CD, Ananthaswamy K, Basappa, Raghavan SC, Rangappa KS. Synthesis and Biological Evaluation of Novel Thiazol-2yl-amine Derivatives as Potential Anticancer Agents. LETT ORG CHEM 2018. [DOI: 10.2174/1570178614666170907122026] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Chaithanya Somu
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore-570006, India
| | - Mahesh Hegde
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore-570006, India
| | | | - Ananda Hanumappa
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore-570006, India
| | - Mrinal Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
| | - Kachigere B. Harsha
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore-570006, India
| | - Chakrabhavi D. Mohan
- Department of Studies in Molecular Biology, University of Mysore, Manasagangotri, Mysore-570006, India
| | - Kavya Ananthaswamy
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
| | - Basappa
- Department of Chemistry, Central College, Bangalore University, Bangalore-570001, India
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
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38
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Javadekar SM, Yadav R, Raghavan SC. DNA structural basis for fragility at peak III of BCL2 major breakpoint region associated with t(14;18) translocation. Biochim Biophys Acta Gen Subj 2017; 1862:649-659. [PMID: 29246583 DOI: 10.1016/j.bbagen.2017.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/23/2017] [Accepted: 12/07/2017] [Indexed: 12/23/2022]
Abstract
Maintaining genome integrity is crucial for normal cellular functions. DNA double-strand breaks (DSBs), when unrepaired, can potentiate chromosomal translocations. t(14;18) translocation involving BCL2 gene on chromosome 18 and IgH loci at chromosome 14, could lead to follicular lymphoma. Molecular basis for fragility of translocation breakpoint regions is an active area of investigation. Previously, formation of non-B DNA structures like G-quadruplex, triplex, B/A transition were investigated at peak I of BCL2 major breakpoint region (MBR); however, it is less understood at peak III. In vitro gel shift assays show faster mobility for MBR peak III sequences, unlike controls. CD studies of peak III sequences reveal a spectral pattern different from B-DNA. Although complementary C-rich stretches exhibit single-strandedness, corresponding guanine-rich sequences do not show DMS protection, ruling out G-quadruplex and triplex DNA. Extrachromosomal assay indicates that peak III halts transcription, unlike its mutated version. Taken together, multiple lines of evidence suggest formation of potential cruciform DNA structure at MBR peak III, which was also supported by in silico studies. Thus, our study reveals formation of non-B DNA structure which could be a basis for fragility at BCL2 breakpoint regions, eventually leading to chromosomal translocations.
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Affiliation(s)
- Saniya M Javadekar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Rakhee Yadav
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India.
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Srivastava S, Dahal S, Naidu SJ, Anand D, Gopalakrishnan V, Kooloth Valappil R, Raghavan SC. DNA double-strand break repair in Penaeus monodon is predominantly dependent on homologous recombination. DNA Res 2017; 24:117-128. [PMID: 28431013 PMCID: PMC5397610 DOI: 10.1093/dnares/dsw059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 12/08/2016] [Indexed: 11/13/2022] Open
Abstract
DNA double-strand breaks (DSBs) are mostly repaired by nonhomologous end joining (NHEJ) and homologous recombination (HR) in higher eukaryotes. In contrast, HR-mediated DSB repair is the major double-strand break repair pathway in lower order organisms such as bacteria and yeast. Penaeus monodon, commonly known as black tiger shrimp, is one of the economically important crustaceans facing large-scale mortality due to exposure to infectious diseases. The animals can also get exposed to chemical mutagens under the culture conditions as well as in wild. Although DSB repair mechanisms have been described in mammals and some invertebrates, its mechanism is unknown in the shrimp species. In the present study, we show that HR-mediated DSB repair is the predominant mode of repair in P. monodon. Robust repair was observed at a temperature of 30 °C, when 2 µg of cell-free extract derived from hepatopancreas was used for the study. Although HR occurred through both reciprocal recombination and gene conversion, the latter was predominant when the bacterial colonies containing recombinants were evaluated. Unlike mammals, NHEJ-mediated DSB repair was undetectable in P. monodon. However, we could detect evidence for an alternative mode of NHEJ that uses microhomology, termed as microhomology-mediated end joining (MMEJ). Interestingly, unlike HR, MMEJ was predominant at lower temperatures. Therefore, the results suggest that, while HR is major DSB repair pathway in shrimp, MMEJ also plays a role in ensuring the continuity and stability of the genome.
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Affiliation(s)
- Shikha Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sumedha Dahal
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sharanya J Naidu
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Deepika Anand
- ICAR-Central Institute of Fisheries Education, Mumbai 400 061, India
| | - Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | | | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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40
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Nishana M, Nilavar NM, Kumari R, Pandey M, Raghavan SC. HIV integrase inhibitor, Elvitegravir, impairs RAG functions and inhibits V(D)J recombination. Cell Death Dis 2017; 8:e2852. [PMID: 28569776 PMCID: PMC5520896 DOI: 10.1038/cddis.2017.237] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 03/24/2017] [Accepted: 04/05/2017] [Indexed: 12/13/2022]
Abstract
Integrase inhibitors are a class of antiretroviral drugs used for the treatment of AIDS that target HIV integrase, an enzyme responsible for integration of viral cDNA into host genome. RAG1, a critical enzyme involved in V(D)J recombination exhibits structural similarity to HIV integrase. We find that two integrase inhibitors, Raltegravir and Elvitegravir, interfered with the physiological functions of RAGs such as binding, cleavage and hairpin formation at the recombination signal sequence (RSS), though the effect of Raltegravir was limited. Circular dichroism studies demonstrated a distinct change in the secondary structure of RAG1 central domain (RAG1 shares DDE motif amino acids with integrases), and when incubated with Elvitegravir, an equilibrium dissociation constant (Kd) of 32.53±2.9 μM was determined by Biolayer interferometry, leading to inhibition of its binding to DNA. Besides, using extrachromosomal assays, we show that Elvitegravir inhibited both coding and signal joint formation in pre-B cells. Importantly, treatment with Elvitegravir resulted in significant reduction of mature B lymphocytes in 70% of mice studied. Thus, our study suggests a potential risk associated with the use of Elvitegravir as an antiretroviral drug, considering the evolutionary and structural similarities between HIV integrase and RAGs.
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Affiliation(s)
| | - Namrata M Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Rupa Kumari
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Monica Pandey
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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41
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Hegde M, Vartak SV, Kavitha CV, Ananda H, Prasanna DS, Gopalakrishnan V, Choudhary B, Rangappa KS, Raghavan SC. A Benzothiazole Derivative (5g) Induces DNA Damage And Potent G2/M Arrest In Cancer Cells. Sci Rep 2017; 7:2533. [PMID: 28566733 PMCID: PMC5451441 DOI: 10.1038/s41598-017-02489-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 04/12/2017] [Indexed: 11/25/2022] Open
Abstract
Chemically synthesized small molecules play important role in anticancer therapy. Several chemical compounds have been reported to damage the DNA, either directly or indirectly slowing down the cancer cell progression by causing a cell cycle arrest. Direct or indirect reactive oxygen species formation causes DNA damage leading to cell cycle arrest and subsequent cell death. Therefore, identification of chemically synthesized compounds with anticancer potential is important. Here we investigate the effect of benzothiazole derivative (5g) for its ability to inhibit cell proliferation in different cancer models. Interestingly, 5g interfered with cell proliferation in both, cell lines and tumor cells leading to significant G2/M arrest. 5g treatment resulted in elevated levels of ROS and subsequently, DNA double-strand breaks (DSBs) explaining observed G2/M arrest. Consistently, we observed deregulation of many cell cycle associated proteins such as CDK1, BCL2 and their phosphorylated form, CyclinB1, CDC25c etc. Besides, 5g treatment led to decreased levels of mitochondrial membrane potential and activation of apoptosis. Interestingly, 5g administration inhibited tumor growth in mice without significant side effects. Thus, our study identifies 5g as a potent biochemical inhibitor to induce G2/M phase arrest of the cell cycle, and demonstrates its anticancer properties both ex vivo and in vivo.
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Affiliation(s)
- Mahesh Hegde
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.,Department of Studies in Chemistry, University of Mysore, Mysuru, 570006, India
| | - Supriya V Vartak
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | | | - Hanumappa Ananda
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Doddakunche S Prasanna
- Department of Nanotechnology, Visvesvaraya Technological University, Center for Postgraduate Studies, Bengaluru Region, Muddenahalli, Chikkaballapur, Bangalore, 562101, India
| | - Vidya Gopalakrishnan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.,Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, 560100, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City, Bangalore, 560100, India
| | | | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.
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42
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Vartak SV, Iyer D, Santhoshkumar T, Sharma S, Mishra A, Goldsmith G, Srivastava M, Srivastava S, Karki SS, Surolia A, Choudhary B, Raghavan SC. Novel BCL2 inhibitor, Disarib induces apoptosis by disruption of BCL2-BAK interaction. Biochem Pharmacol 2017; 131:16-28. [DOI: 10.1016/j.bcp.2017.02.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 02/16/2017] [Indexed: 11/28/2022]
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43
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Krishnaraj J, Kowshik J, Sebastian R, Raghavan SC, Nagini S. Exposure to welding fumes activates DNA damage response and redox-sensitive transcription factor signalling in Sprague-Dawley rats. Toxicol Lett 2017; 274:8-19. [DOI: 10.1016/j.toxlet.2017.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 03/30/2017] [Accepted: 04/03/2017] [Indexed: 10/19/2022]
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44
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45
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Ananda H, Sharath Kumar KS, Nishana M, Hegde M, Srivastava M, Byregowda R, Choudhary B, Raghavan SC, Rangappa KS. Regioselective synthesis and biological studies of novel 1-aryl-3, 5-bis (het) aryl pyrazole derivatives as potential antiproliferative agents. Mol Cell Biochem 2016; 426:149-160. [DOI: 10.1007/s11010-016-2887-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/10/2016] [Indexed: 02/08/2023]
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46
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Ghoshal N, Sharma S, Banerjee A, Kurkalang S, Raghavan SC, Chatterjee A. Influence of reduced glutathione on end-joining of DNA double-strand breaks: Cytogenetical and molecular approach. Mutat Res 2016; 795:1-9. [PMID: 27883910 DOI: 10.1016/j.mrfmmm.2016.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 10/06/2016] [Accepted: 10/22/2016] [Indexed: 10/20/2022]
Abstract
Radiation induced DNA double-strand breaks (DSB) are the major initial lesions whose misrejoining may lead to exchange aberrations. However, the role of glutathione (GSH), a major cellular thiol, in regulating cell's sensitivity to DNA damaging agents is not well understood. Influence of endogenous GSH on the efficiency of X-rays and bleomycin (Blem) induced DNA DSBs end-joining has been tested here cytogenetically, in human lymphocytes and Hct116 cells. In another approach, oligomeric DNA (75bp) containing 5'-compatible and non-compatible overhangs mimicking the endogenous DSB were for rejoining in presence of cell-free extracts from cells having different endogenous GSH levels. Frequency of aberrations, particularly exchange aberrations, was significantly increased when Blem was combined with radiation. The exchange aberration frequency was further enhanced when combined treatment was given at 4°C since DNA lesions are poorly repaired at 4°C so that a higher number of DNA breaks persist and interact when shifted from 4°C to 37°C. The exchange aberrations increased further when the combined treatment was given to Glutathione-ester (GE) pre-treated cells, indicating more frequent rejoining of DNA lesions in presence of higher cellular GSH. This is further supported by the drastic reduction in frequency of exchange aberrations but significant increase in incidences of deletions when combined treatment was given to GSH-depleted cells. End-joining efficiency of DNA DSBs with compatible ends was better than for non-compatible ends. End-joining efficiency of testicular and MCF7 cell extracts was better than that of lungs and Hct116 cells. Cell extract made from GE-treated MCF-7 cells provided more efficient end-joining than from untreated and GSH-depleted cells. However, direct addition of GSH to the cell-free extracts showed considerable reduction in end-joining efficiency. Present data indicate that higher endogenous GSH favours rejoining of DNA DSBs (both restitution and illegitimate reunion) which in turn produce more exchange aberrations.
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Affiliation(s)
- Nitin Ghoshal
- Molecular Genetics Laboratory, Department of Biotechnology & Bioinformatics, North-Eastern Hill University, Shillong, Meghalaya-793022, India
| | - Sheetal Sharma
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
| | - Atanu Banerjee
- Molecular Genetics Laboratory, Department of Biotechnology & Bioinformatics, North-Eastern Hill University, Shillong, Meghalaya-793022, India
| | - Sillarine Kurkalang
- Molecular Genetics Laboratory, Department of Biotechnology & Bioinformatics, North-Eastern Hill University, Shillong, Meghalaya-793022, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560 012, India
| | - Anupam Chatterjee
- Molecular Genetics Laboratory, Department of Biotechnology & Bioinformatics, North-Eastern Hill University, Shillong, Meghalaya-793022, India.
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Thomas E, Gopalakrishnan V, Hegde M, Kumar S, Karki SS, Raghavan SC, Choudhary B. A Novel Resveratrol Based Tubulin Inhibitor Induces Mitotic Arrest and Activates Apoptosis in Cancer Cells. Sci Rep 2016; 6:34653. [PMID: 27748367 PMCID: PMC5066224 DOI: 10.1038/srep34653] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/14/2016] [Indexed: 11/14/2022] Open
Abstract
Resveratrol is one of the most widely studied bioactive plant polyphenols which possesses anticancer properties. Previously we have reported synthesis, characterization and identification of a novel resveratrol analog, SS28. In the present study, we show that SS28 induced cytotoxicity in several cancer cell lines ex vivo with an IC50 value of 3–5 μM. Mechanistic evaluation of effect of SS28 in non-small cell lung cancer cell line (A549) and T-cell leukemic cell line (CEM) showed that it inhibited Tubulin polymerization during cell division to cause cell cycle arrest at G2/M phase of the cell cycle at 12–18 h time period. Immunofluorescence studies confirmed the mitotic arrest upon treatment with SS28. Besides, we show that SS28 binds to Tubulin with a dissociation constant of 0.414 ± 0.11 μM. Further, SS28 treatment resulted in loss of mitochondrial membrane potential, activation of Caspase 9 and Caspase 3, leading to PARP-1 cleavage and finally cell death via intrinsic pathway of apoptosis. Importantly, treatment with SS28 resulted in regression of tumor in mice. Hence, our study reveals the antiproliferative activity of SS28 by disrupting microtubule dynamics by binding to its cellular target Tubulin and its potential to be developed as an anticancer molecule.
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Affiliation(s)
- Elizabeth Thomas
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Vidya Gopalakrishnan
- Institute of Bioinformatics and Applied Biotechnology, Electronic City, Bangalore 560 100, India
| | - Mahesh Hegde
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sujeet Kumar
- Department of Pharmaceutical Chemistry, KLE University's College of Pharmacy, Bangalore 560 010, India
| | - Subhas S Karki
- Department of Pharmaceutical Chemistry, KLE University's College of Pharmacy, Bangalore 560 010, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronic City, Bangalore 560 100, India
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48
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Iyer D, Vartak SV, Mishra A, Goldsmith G, Kumar S, Srivastava M, Hegde M, Gopalakrishnan V, Glenn M, Velusamy M, Choudhary B, Kalakonda N, Karki SS, Surolia A, Raghavan SC. Identification of a novel BCL2-specific inhibitor that binds predominantly to the BH1 domain. FEBS J 2016; 283:3408-37. [DOI: 10.1111/febs.13815] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/15/2016] [Accepted: 07/19/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Divyaanka Iyer
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Supriya V. Vartak
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Archita Mishra
- Molecular Biophysics Unit; Indian Institute of Science; Bangalore India
| | - Gunaseelan Goldsmith
- Institute of Bioinformatics and Applied Biotechnology, Electronics City; Bangalore India
| | - Sujeet Kumar
- Department of Pharmaceutical Chemistry; KLE University's College of Pharmacy; Bangalore India
| | - Mrinal Srivastava
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Mahesh Hegde
- Department of Biochemistry; Indian Institute of Science; Bangalore India
| | - Vidya Gopalakrishnan
- Department of Biochemistry; Indian Institute of Science; Bangalore India
- Institute of Bioinformatics and Applied Biotechnology, Electronics City; Bangalore India
| | - Mark Glenn
- Haematology; Department of Molecular and Clinical Cancer Medicine University of Liverpool; UK
| | - Mahesh Velusamy
- Institute of Bioinformatics and Applied Biotechnology, Electronics City; Bangalore India
| | - Bibha Choudhary
- Institute of Bioinformatics and Applied Biotechnology, Electronics City; Bangalore India
| | - Nagesh Kalakonda
- Haematology; Department of Molecular and Clinical Cancer Medicine University of Liverpool; UK
| | - Subhas S. Karki
- Department of Pharmaceutical Chemistry; KLE University's College of Pharmacy; Bangalore India
| | - Avadhesha Surolia
- Molecular Biophysics Unit; Indian Institute of Science; Bangalore India
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Sebastian R, Raghavan SC. Induction of DNA damage and erroneous repair can explain genomic instability caused by endosulfan. Carcinogenesis 2016; 37:929-40. [PMID: 27492056 DOI: 10.1093/carcin/bgw081] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/30/2016] [Indexed: 12/15/2022] Open
Abstract
Endosulfan (ES) is an organochlorine pesticide, speculated to be associated with chromosomal abnormalities and diseases in humans. However, very little is known about the mechanism of its genotoxicity. Using in vivo, ex vivo and in vitro model systems, we show that exposure to ES induces reactive oxygen species (ROS) in a concentration and time-dependent manner. The generation of ROS results in DNA double-strand breaks either directly or in a replication-dependent manner, both in mice and human cells. Importantly, ES-induced DNA damage evokes DNA damage response, resulting in elevated levels of classical non-homologous DNA endjoining (NHEJ), the predominant double-strand break repair pathway in higher eukaryotes. Sequence analyses of NHEJ junctions revealed that ES treatment results in extensive processing of broken DNA, culminating in increased and long junctional deletions, thereby favoring erroneous repair. We also find that exposure to ES leads to significant increase in microhomology-mediated end joining (MMEJ), a LIGASE III-dependent alternative repair pathway. Therefore, we demonstrate that ES induces DNA damage and genomic instability, alters DNA damage response thereby promoting erroneous DNA repair.
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Affiliation(s)
- Robin Sebastian
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560 012, India
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50
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Das K, Srivastava M, Raghavan SC. GNG Motifs Can Replace a GGG Stretch during G-Quadruplex Formation in a Context Dependent Manner. PLoS One 2016; 11:e0158794. [PMID: 27414642 PMCID: PMC4945072 DOI: 10.1371/journal.pone.0158794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/22/2016] [Indexed: 12/13/2022] Open
Abstract
G-quadruplexes are one of the most commonly studied non-B DNA structures. Generally, these structures are formed using a minimum of 4, three guanine tracts, with connecting loops ranging from one to seven. Recent studies have reported deviation from this general convention. One such deviation is the involvement of bulges in the guanine tracts. In this study, guanines along with bulges, also referred to as GNG motifs have been extensively studied using recently reported HOX11 breakpoint fragile region I as a model template. By strategic mutagenesis approach we show that the contribution from continuous G-tracts may be dispensible during G-quadruplex formation when such motifs are flanked by GNGs. Importantly, the positioning and number of GNG/GNGNG can also influence the formation of G-quadruplexes. Further, we assessed three genomic regions from HIF1 alpha, VEGF and SHOX gene for G-quadruplex formation using GNG motifs. We show that HIF1 alpha sequence harbouring GNG motifs can fold into intramolecular G-quadruplex. In contrast, GNG motifs in mutant VEGF sequence could not participate in structure formation, suggesting that the usage of GNG is context dependent. Importantly, we show that when two continuous stretches of guanines are flanked by two independent GNG motifs in a naturally occurring sequence (SHOX), it can fold into an intramolecular G-quadruplex. Finally, we show the specific binding of G-quadruplex binding protein, Nucleolin and G-quadruplex antibody, BG4 to SHOX G-quadruplex. Overall, our study provides novel insights into the role of GNG motifs in G-quadruplex structure formation which may have both physiological and pathological implications.
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Affiliation(s)
- Kohal Das
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Mrinal Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Sathees C. Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
- * E-mail:
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